Wacha, the 22-year-old right-hander who won four postseason games for St. Louis last fall, gave up three singles in his third start of the spring. He mixed in his cutter this time, saying he used six or seven.

“I feel I needed something to go along with the curveball and changeup, just to put something in the back of their heads,” Wacha said. “Hopefully it’ll catch ‘em off guard.”

He used “six or seven” against the Astros and says he has complete confidence in the new pitch.

Manager Mike Matheny said Wacha “fooled around with it a little” last season, but he didn’t have much time to experiment down the stretch in September, when he filled in for the Cardinals.

Scruggs and Carpenter had RBI hits for the Cardinals in the second inning. Kolten Wong, Scruggs and Carpenter had extra-base hits in the fourth, and Astros center fielder Dexter Fowler prevented a fourth with a running catch of Randal Grichuk’s 400-foot drive to the warning track in center field.

Astros: Cosart gave up five hits, two walks and five earned runs in 3 1/3 innings. “Out of the stretch my timing’s a little off. That’s what got me in trouble today,” said Cosart, who is trying out a new delivery. “It’s not a major fix, just something we can talk about and build on.”

“Now, we’d be lying if we didn’t say Adam Wainwright didn’t have a spot in this rotation,” Matheny said. “But after that, we show up here watching guys compete because that’s what they’re made to do, that what they’re paid to do. And I think making any bold statement too early discourages somebody, for sure, and could distract others.”

“I don’t really look at it as seeing guys in the clubhouse and thinking: I’m competing against him for their job,” Wacha said. “I’m just competing within myself, I guess, just continuing to work on stuff.”

TRAINER’S ROOM

Cardinals: Matheny is concerned that outfielder Oscar Taveras, the team’s top prospect, might be taking Thursday’s optioning to Triple-A Memphis the wrong way. Taveras missed most of last season after ankle surgery and had hamstring trouble this spring.

“A step back is not necessarily a bad thing if it’s handled the right way,” Matheny said. “The initial step back happened when he got hurt last year.”

NICE IMPRESSION

Marwin Gonzalez has played three infield positions with the Astros this spring and Porter said he can play all three outfield spots.